.\"
.\" $Id: parse_open_flags.3,v 1.1 2000/07/27 16:59:03 alaffin Exp $
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.TH PARSE_OPEN_FLAGS 3 07/25/2000 "Linux Test Project"
.SH NAME
parse_open_flags \- converts open flag symbols into bitmask
.br
openflags2symbols \- converts open flag bitmask into symbols

.SH SYNOPSIS
int
.br
\fBparse_open_flags\fR(\fIsymbols, badname\fR)
.br
char *\fIsymbols\fR;
.br
char **\fIbadname\fR;

char *
.br
\fBopenflags2symbols\fR(\fIopenflags, sep, mode\fR)
.br
int \fIopenflags\fR;
.br
char *\fIsep\fR;
.br
int \fImode\fR;

.SH DESCRIPTION
The \fBparse_open_flags\fR function can be used to convert
a list of comma separated \fBopen\fR(2) flag symbols (i.e. O_TRUNC)
into the bitmask that can be used by open(2).
If a symbol is unknown and \fIbadname\fR is not NULL, \fIbadname\fR
will updated to point that symbol in \fIsymbols\fR.
\fBParse_open_flags\fR will return -1 on this error.
Otherwise \fBparse_open_flags\fR will return the open flag bitmask.
If \fBparse_open_flags\fR returns, \fIstring\fR will left unchanged.

The \fBopenflags2symbols\fR function attempts to convert open flag
bits into human readable  symbols (i.e. O_TRUNC).  If there
are more than one symbol, the \fBsep\fR string will be placed as
a separator between symbols.  Commonly used separators would
be a comma "," or pipe "|".  If \fImode\fR is one and not all
\fIopenflags\fR bits can be converted to symbols, the \fBUNKNOWN\fR
symbol will be added to return string.
Openflags2symbols will return the identified symbols.
If no symbols are recognized the return value will be a empty
string or the \fBUNKNOWN\fR symbol.

If the \fBO_WRONLY\fR and \fBO_RDWR\fR bits are not set, \fBopenflags2symbols\fR
assumes that \fBO_RDONLY\fR symbol is wanted.

.SH "SEE ALSO"
open(2),
/usr/include/sys/fcntl.h.

.SH EXAMPLES
.nf
.in +3
/*
 * The following code provides a UNIT test main for
 * parse_open_flags and openflags2symbols functions.
 */
#include <stdio.h>

main(argc, argv)
int argc;
char **argv;
{
    int bits;
    int ret;
    char *err;

    if (argc == 1 ) {
        printf("Usage: %s openflagsbits\n\t%s symbols\n", argv[0], argv[0]);
        exit(1);
    }

    if ( sscanf(argv[1], "%i", &bits) == 1 ) {
        printf("openflags2symbols(%#o, \",\", 1) returned %s\n",
            bits, openflags2symbols(bits, ",", 1));

    } else {
        ret=parse_open_flags(argv[1], &err);
        if ( ret == -1 )
            printf("parse_open_flags(%s, &err) returned -1, err = %s\n",
                argv[0], err);
        else
            printf("parse_open_flags(%s, &err) returned %#o\n", argv[0], ret);
    }

    exit(0);
}

.in -3
.fi

.SH LIMITATIONS
Currently (06/96) all known symbols are coded into \fBopenflags2symbols\fR.
If new open flags are added this function code will have to updated
to know about them or they will not be recognized.

The static space where \fBopenflags2symbols\fR stores open flag
symbols with callers separators is limited to 512 characters.
This should be large enough for most open flags symbols as long as the
separator is kept short.

